As portable electronics devices, such as e-readers, video displays, and other gadgetry continue to gain worldwide acceptance, the demand for improved mechanical durability in these devices grows. Many of these devices contain thin film transistors, most often comprising glass support substrates. For those products using glass as the backplane substrate, an impact with the floor, harsh environmental conditions, or similar event could cause device failure. For example, fracturing of the glass backplane substrate is a dominant failure mode in current e-readers.
Glass is viewed by device manufacturers as limiting the device durability, and attempts have been made to replace it with other materials such as metal sheets (e.g. aluminum or stainless steel) and polymer films (polyethylene terephthalate or polyethylene naphthalate). Although metal and polymer films are non-brittle, these materials also have limitations. Metal films are often too rough and require a planarization layer and polymer films are prone to solvent incompatibility and have thermal-dimensional limitations. Additionally, metal and polymer substrates may provide additional compatibility issues not present with glass when used as a support substrate.
The ideal substrate would be able to withstand increased temperatures, provide a surface with low roughness, be unaffected by processing solvents, and be able to withstand everyday final product-type abuse. Current substrates fail to meet at least one of these important factors, leading to an unmet need to find novel substrates that have improved performance.